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WO1998039866A1 - Systeme et procede permettant de determiner des caracteristiques de bout en bout d'un canal de communication de donnees - Google Patents

Systeme et procede permettant de determiner des caracteristiques de bout en bout d'un canal de communication de donnees Download PDF

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Publication number
WO1998039866A1
WO1998039866A1 PCT/US1998/004271 US9804271W WO9839866A1 WO 1998039866 A1 WO1998039866 A1 WO 1998039866A1 US 9804271 W US9804271 W US 9804271W WO 9839866 A1 WO9839866 A1 WO 9839866A1
Authority
WO
WIPO (PCT)
Prior art keywords
digital
signal
bit
data
splk
Prior art date
Application number
PCT/US1998/004271
Other languages
English (en)
Inventor
Bert A. Davenport
James A. Renkel
Peter P. Jankus
Original Assignee
3Com Corporation
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US08/816,699 external-priority patent/US6088334A/en
Application filed by 3Com Corporation filed Critical 3Com Corporation
Priority to DE69801477T priority Critical patent/DE69801477T2/de
Priority to EP98910176A priority patent/EP0916202B1/fr
Priority to CA002254960A priority patent/CA2254960C/fr
Priority to AT98910176T priority patent/ATE205031T1/de
Priority to AU64477/98A priority patent/AU6447798A/en
Publication of WO1998039866A1 publication Critical patent/WO1998039866A1/fr

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q11/00—Selecting arrangements for multiplex systems
    • H04Q11/04—Selecting arrangements for multiplex systems for time-division multiplexing
    • H04Q11/0428—Integrated services digital network, i.e. systems for transmission of different types of digitised signals, e.g. speech, data, telecentral, television signals
    • H04Q11/0435—Details
    • H04Q11/045—Selection or connection testing arrangements
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J3/00—Time-division multiplex systems
    • H04J3/02—Details
    • H04J3/12—Arrangements providing for calling or supervisory signals
    • H04J3/125—One of the channel pulses or the synchronisation pulse is also used for transmitting monitoring or supervisory signals
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L25/00—Baseband systems
    • H04L25/38—Synchronous or start-stop systems, e.g. for Baudot code
    • H04L25/40—Transmitting circuits; Receiving circuits
    • H04L25/49—Transmitting circuits; Receiving circuits using code conversion at the transmitter; using predistortion; using insertion of idle bits for obtaining a desired frequency spectrum; using three or more amplitude levels ; Baseband coding techniques specific to data transmission systems
    • H04L25/4917—Transmitting circuits; Receiving circuits using code conversion at the transmitter; using predistortion; using insertion of idle bits for obtaining a desired frequency spectrum; using three or more amplitude levels ; Baseband coding techniques specific to data transmission systems using multilevel codes
    • H04L25/4927—Transmitting circuits; Receiving circuits using code conversion at the transmitter; using predistortion; using insertion of idle bits for obtaining a desired frequency spectrum; using three or more amplitude levels ; Baseband coding techniques specific to data transmission systems using multilevel codes using levels matched to the quantisation levels of the channel
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/14—Two-way operation using the same type of signal, i.e. duplex
    • H04L5/1438—Negotiation of transmission parameters prior to communication
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q11/00—Selecting arrangements for multiplex systems
    • H04Q11/04—Selecting arrangements for multiplex systems for time-division multiplexing
    • H04Q11/0428—Integrated services digital network, i.e. systems for transmission of different types of digitised signals, e.g. speech, data, telecentral, television signals
    • H04Q11/0435—Details
    • H04Q11/0457—Connection protocols

Definitions

  • TITLE System and Method for Determining End-to-End Characteristics of a
  • the present invention relates to a method and apparatus for detecting characteristics of a communication channel.
  • the present invention may be utilized to determine if a communication channel is digital end-to-end.
  • the present method and apparatus may determine whether an Integrated Services Digital Network ("ISDN") to ISDN connection is all digital.
  • ISDN Integrated Services Digital Network
  • the present method and apparatus may determine whether an ISDN to Tl/El, or Tl/El to Tl/El, connection is all digital. Impairments in the digital connection may also be detected by the apparatus and method of the present invention.
  • ISDN Integrated Services Digital Network
  • Tl/El Integrated Services Digital Network
  • Impairments in the digital connection may also be detected by the apparatus and method of the present invention.
  • some known systems send digital data over a channel that is billed as analog. Such systems do not verify that the channel is actually digital before sending the data.
  • the communication channel in an ISDN- to-ISDN connection is determined to be end-to-end digital, the data can be sent and billed as an analog call.
  • a second call attempt can be made requesting (and paying for) a digital call.
  • an ISDN to Tl/El, or Tl/El to Tl El, connection is determined to be all digital, digital data transfer rates of up to 62.666 kbps/B channel full-duplex can be achieved utilizing the method and apparatus of the present invention.
  • Use a scrambler to prevent the network from compressing the data Use zero byte suppression to communicate digitally over a link that converts 00 to 02; Determine if one or more robbed bits are present in a communication channel; and/or Determine where one or more robbed bits are located and use 100% of the remaining non-robbed bits for data.
  • Figure 1 is a block diagram showing a connection between two devices having digital connectivity to the telephone network.
  • Figure 2 is a block diagram showing a sequence of initial negotiations between the calling device and the answering device shown in Figure 1.
  • Figure 3 is a block diagram showing more fully the content of block FF in Figure 2.
  • Figure 4 is an expanded diagram of the contents of block SQA in Figure 2.
  • Figures 5 A and 5B are an expanded diagram of the contents of block SPl in Figure 2 and a tabular description of the contents, respectively.
  • Figure 6 is an expanded diagram of block E in Figure 2.
  • Figure 7 is a block diagram of a transmitter in the calling device and the answering device shown in Figure 1.
  • FIG. 1 is a block diagram showing a connection between two devices having digital connectivity to the telephone network.
  • a calling device 10 has a digital connection to the General Switched Telephone Network ("GSTN") 12.
  • GSTN General Switched Telephone Network
  • An answering device 14 also has a digital connection to the GSTN 12.
  • GSTN General Switched Telephone Network
  • Figure 2 shows the negotiation between the calling and answering devices 10 and 14 using the present system.
  • the calling and answering devices are preferably modems.
  • the following is a description of what each of the modems 10, 14 is doing during negotiation over data communication channel 16, as shown in Figure 1.
  • Figure 1 shows a calling device 10 communicating over a data communication line 16 with an answering device 14.
  • the line 16 may or may not include an analog segment.
  • the devices 10,14 utilize the present system to determine the characteristics of the line 16, including whether the line 16 is entirely digital or it includes an analog segment and whether the line includes any digital impairments.
  • digital impairments refers to limitations on the content of the data sent over the line, such as robbed bit signaling (RBS) or a restricted channel.
  • RBS robbed bit signaling
  • the an entity such as a telephone company, operating the line utilizes the least significant bit of selected (e.g., every sixth) byte for overhead purposes.
  • restricted channel rather than a nonrestricted channel, the data sent over the line must have a minimum one's density: there is a limitation on the number of zeros that may validly be placed in a consecutive series. (In some telecommunication systems, such ones density is used to ensure synchronization.)
  • regulatory bodies may impose a limitation on the maximum power that may be carried by the line 16. Such power limitations may restrict the energy (in terms of power) that a modem may transmit receive during various time intervals of predetermined length, such as 250 milliseconds or 3 seconds. Calling modem procedures
  • the calling modem will transmit all marks (bytes of FF hex) until it receives the SQA sequence from the answering modem.
  • the composition of the SQA sequence is shown in Figure 4.
  • the SQA sequence will allow the modem to determine the following: Is the channel partially analog, or is it all digital?
  • the calling modem upon receiving the SQA sequence from the answering modem, the calling modem will transmit the SQA sequence until it receives the SPl sequence from the answering modem.
  • the SQA sequence, or probing signal is shown more fully in Figure 4.
  • the sequence may thus be divided into three subparts: (1) 7+6n bytes of 7E, where n is preferably 290; (2) 7 bytes of 00, and (3) a sequence of digital codewords, which corresponds to an analog signal with a 4,000 Hz frequency, l A the maximum allowable amplitude, and an increasing dc offset voltage.
  • the digital codewords are preferably eight bit PCM codewords or PCM codes.
  • the first subpart of SQA, 7E in Figure 4 is a low power transmission. This allows the probing signal to meet the maximum power constraints imposed on the line by decreasing the average power transmitted during the SQA sequence.
  • the first subpart effectively "pads" the length of the probing signal, such that the length of the entire probing signal (all three subparts) is a multiple of 6 bytes.
  • RBS may be more easily detected, since, in many environments, RBS occurs only in every sixth byte at DSO.
  • the SQA sequence is known to the answering device and has a predetermined length, the location and number of robbed bits are determined from the SQA sequence.
  • the second subpart of SQA, 00 in Figure 4 is sent by the calling modem to test whether the line is a restricted channel or a clear channel.
  • the answering modem effectively knows that if the received signal includes ones in the portion corresponding to the second subpart of the probing signal, the telephone company has probably inserted ones in order to maintain a minimum ones density in the transmitted data. Thus, in such a case, the channel is restricted.
  • This type of density restriction may be satisfied, along with all other density restrictions, by inserting a 1 after each string of at most seven consecutive zeros. It should be noted that, since the insertion is done before the data is inverted for transmission, this algorithm may be implemented by inserting a zero after each string of at most seven ones. It should further be noted that the "zero bit insertion deletion" (ZBID) scheme used with HDLC/SDLC specifies insertion of a zero after six consecutive ones in the data stream to avoid false flag patterns (0, 6 ones, 0). The flag pattern was chosen to be distinguishable from an abort pattern (0, 7 or more ones) and the idle pattern (continuous ones).
  • the quantizer may be for example a ⁇ -law quantizer, as is used in North America and Japan, or an A-law quantizer , as is used in Europe. In the digital domain, each of the quantizer levels may be represented by a different eight bit codeword. If the signal received by the answering device lacks the full range of the transmitted probing signal, the answering modem may effectively "know" of the digital coding system used in the line.
  • the presence of a digital attenuator pad in the connection will cause the codewords in the third subpart of SQA to be adjusted in a fixed manner.
  • the answering device which knows what the third subpart should be, analyzes the received signal and may thereby identify the presence and characteristics of the pad.
  • the relatively high frequency and amplitude of the probe signal in the third subpart are difficult for an analog converter to translate. Indeed, in many telephone company lines, a filter substantially attenuates signals even approaching 4,000 Hz. If the received signal does not correspond to the transmitted probe signal, the answering modem may know that an analog segment lies in the line.
  • the total length of the probing signal used in the preferred embodiment is 256 bytes + 7 bytes + 7 bytes + (290 * 6), or 2010, bytes long.
  • the answering device monitors, during the entire predetermined probing signal, to detect whether the received signal has the least significant bit different than the least significant bit of the probe signal. If so, the answering modem effectively knows that the telephone company line utilizes RBS. In one embodiment, the modems then simply know to communicate at 56 kbps rather than, for example, 64 kbps. In other embodiments, the modems simply do not send data in the least significant bit ("LSB") of any byte because of RBS. The data transmission speed of such modems is accordingly limited to a top speed of 56 kbps.
  • LSB least significant bit
  • FIG 5 is an expanded diagram of the contents of block SPl in Figure 2.
  • the SPl sequence is an indication of capabilities of the modem and a request to turn on or off various features and speeds in the modem.
  • the calling modem Upon receiving the SPl sequence from the answering modem, the calling modem will transmit the SPl sequence until it receives the E sequence.
  • Figure 6 is an expanded diagram of block E in Figure 2.
  • the calling modem Upon receiving the E sequence from the answering modem, the calling modem will transmit the E sequence (fixed length of 5 bytes) followed by data.
  • the calling modem Upon receiving the data from the answering modem, the calling modem will unclamp its receive data and will proceed to receive data from the answering modem.
  • the answering modem will transmit the SQA sequence until it receives the SQA sequence form the calling modem.
  • the SQA sequence will allow the modem to determine the following: Is the channel partially analog, or is it all digital?
  • the answering modem Upon receiving the SQA sequence from the calling modem, the answering modem will transmit the SPl sequence until it receives the SPl sequence from the calling modem.
  • the SPl sequence is an indication of capabilities and of the modem and a request to turn on or off various features and speeds in the modem.
  • the answering modem Upon receiving the SPl sequence from the calling modem, the answering modem will transmit the E sequence (fixed length of 5 bytes) followed by data.
  • the calling modem Upon receiving the data from the calling modem, the calling modem will unclamp its receive data and will proceed to receive data from the calling modem.
  • One aspect of the present system relates to the detection stage: by sending the SQA pattern, the present system has the ability to:
  • a pad is an adjustment of a digital signal, in one of a predetermined number of different ways, to emulate or mimic the attenuation that would have occurred if the signal had been sent on an analog line rather than a digital line. By noting the systematic padding of the probe signal, the modems may adjust their transmission characteristics to compensate for such padding).
  • Another aspect of the invention relates to the data phase: how can the modems may transmit the fastest possible speed given the impairments that are on the line/data communication channel.
  • the present system has the ability to:
  • the present method can determine the exact number and exact location of the RBS which allows faster data transmission than known methods. This is so because if there is just 1 bit robbed by RBS, the preferred method and apparatus described herein may transmit at up to 62,666bps. In fact, with any number or robbed bits between 1 and 5, the preferred method and apparatus provide data transfer rates in excess of 56 Kbps. In a typical network connection, 0-3 robbed bits may be encountered. Finding 4-6 robbed bits appears to be fairly rare.
  • the presently described system will detect the "digital impairment" of digital attenuator pads and could compensate for it, running at a reduced speed, but still running faster than an analog modem. Because the present system sends all 256 PCM codes, if there are any digital impairments that we are currently unaware of, it is very likely that we could detect and handle them with our current SQA sequence.
  • a typical digital network may see a transmitted data stream as being compressible. If, however, the transmitted data stream is compressed by the network, the data stream will likely be corrupted and the connection may fail.
  • Use of a scrambler as described herein makes the transmitted data stream appear as wide-band white noise (i.e. uncompressible). Therefore, the network will not compress the transmitted data stream.
  • an ISDN to ISDN (basic rate or primary rate) connection is determined to be all digital
  • digital data transfer at rates up to 64kbps/B channel full-duplex can be achieved while the customer is billed for an analog call, which is typically billed at a lower rate than a customer would be billed for a digital call.
  • each block shown in Figure 7, except for Byte Conversion, may be turned on or off individually to meet the requirements of the particular network channel:
  • RBS synchronization Each modem's transmitter is synchronized with the remote modem's receiver which is synchronized with the robbed bits in that particular network path (if any are present).
  • the transmitter takes advantage of the fact that it knows if a robbed bit is present in each of the six possible time slots. Each time slot is 8 bits (one byte) long, and the six time slots are periodic i.e., if there is a robed bit in the first time slot, there will be a robbed bit in every sixth byte thereafter (in the same time slot) and these bits together we call "one robbed bit". So, there is a possibility of having from 0-6 robbed bits.
  • the transmitter will only transmit 7 bits of user data.
  • the 8 th bit will be forced to binary one and will be placed in the position of the robbed bit (this happens in the Byte Conversion routine).
  • the 7 bits of user data will not be corrupted by the RBS, only the 8 th bit (not user data) will be corrupted.
  • the scrambler takes the output of the previous section (which will be either 7 or 8 bits) and scrambles it using standard scrambling techniques to create wide-band white noise energy.
  • the network will monitor the call for a duration of time to determine if the data is compressible. If it is, the network will compress the data. This would entirely corrupt the communication between two digital modems. To prevent the network from turning on the compressors, we can scramble the data.
  • the scrambler will create a statistically controlled output which will minimize the output of the Zero Byte Suppresser.
  • the zero byte suppresser takes the output from the previous section (which will be either 7 or 8 bits) and runs it through the following algorithm: If there are ever 7 bits of "binary zero" in a row, insert a "binary one" into the data stream. This algorithm ensures that minimum one's density requirements are met in the network. Note that this routine outputs the same number of bits that it received as an input and it buffers any additional data caused by the bit insertion. The buffered data is combined with the input of the next byte. If there is ever enough data buffered to transmit entirely out of the buffer, that action will be performed.
  • Byte Conversion The byte conversion routine will output 8 bits of data. If its input was 8 bits, it passes the input data to its output without changing it. If its input was 7 bits, it will insert a "binary one" into the byte at the location where the robbed bit will be, and it will output the 8 bits.
  • Pad Mapper Pad Mapper
  • the pad mapper takes the output from the previous section (which will be 8 bits) and it maps the data in such a way as to avoid sending any PCM codes that (due to the digital pad) would result in an ambiguous code at the receiver. Note that if the Zero Byte Suppression and the Pad Mapper are turned on at the same time, they will need to share information to ensure that their respective functions are achieved.
  • the final output is transmitted onto a digital link on the General Switched Telephone Network.
  • the receiver of the remote modem will have knowledge of which of the above blocks are turned on in the transmitter and knowledge of any additional specific information about the transmitter's configuration that it needs in order to reverse the operations of the transmitter and decode the data.
  • Data transported over such a link may be bit * transparent, an HDLC-framed protocol (i.e V.120, PPP), V.110 encoding,
  • the background loop is essentially
  • reset_i 11 initialize stos i 11 ptr mar *,ar2 lar ar2,#stos_il l splk #vfc_probe_results,* lar ar2,#vfc_probe_results rptz #24 sacl *+ mar *,arl lacl #stos_stats ; report rdata_on to SV b queue status
  • lacl #8 Assume 64Kbps interworking (8bit/baud) xc 1,TC ; If yes, then set the number of TX bits sub # ⁇ ; per "baud” to 7 (56Kbps) sacl txnbit ; Set appropriate bits/symbol xc 2,TC ; If 56K, then set the number of bits splk #07fh,txmask ; mask 7 bits (56kbps) ldp #7
  • PCM code server to server call with scrambler? cc scram_v32orig,tc ; call PCM code server to server TX routine

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Physics & Mathematics (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Quality & Reliability (AREA)
  • Communication Control (AREA)
  • Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)
  • Mobile Radio Communication Systems (AREA)
  • Time-Division Multiplex Systems (AREA)
  • Small-Scale Networks (AREA)

Abstract

La présente invention concerne un procédé de détermination des caractéristiques d'un canal de communication de données entre un premier et un second dispositifs de communication de données. Le procédé consiste d'abord à envoyer un signal de sonde numérique à basse puissance sur le canal, du premier vers le second dispositif de communication de données. Le procédé consiste ensuite à envoyer un second signal de sonde numérique correspondant à un signal analogique comprenant un signal de fréquence relativement élevée avec une composante courant continu variant avec le temps, du premier vers le second dispositif de communication de données. Le second dispositif de communication de données reçoit un signal, le signal reçu correspondant aux signaux de sonde envoyés par le premier dispositif. En outre, le second dispositif de communication de données détermine si le signal reçu s'écarte d'une norme prédéterminée.
PCT/US1998/004271 1997-03-07 1998-03-04 Systeme et procede permettant de determiner des caracteristiques de bout en bout d'un canal de communication de donnees WO1998039866A1 (fr)

Priority Applications (5)

Application Number Priority Date Filing Date Title
DE69801477T DE69801477T2 (de) 1997-03-07 1998-03-04 System und verfahren zur bestimmung der end-zu-end-eigenschaften eines kommunikationskanals
EP98910176A EP0916202B1 (fr) 1997-03-07 1998-03-04 Systeme et procede permettant de determiner des caracteristiques de bout en bout d'un canal de communication de donnees
CA002254960A CA2254960C (fr) 1997-03-07 1998-03-04 Systeme et procede permettant de determiner des caracteristiques de bout en bout d'un canal de communication de donnees
AT98910176T ATE205031T1 (de) 1997-03-07 1998-03-04 System und verfahren zur bestimmung der end-zu- end-eigenschaften eines kommunikationskanals
AU64477/98A AU6447798A (en) 1997-03-07 1998-03-04 System and method for determining end-to-end characteristics of a data communication channel

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US4048797P 1997-03-07 1997-03-07
US60/040,487 1997-03-07
US08/816,699 US6088334A (en) 1997-03-13 1997-03-13 System and method for determining end-to-end characteristics of a data communication channel
US08/816,699 1997-03-13

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WO1998039866A1 true WO1998039866A1 (fr) 1998-09-11

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EP (1) EP0916202B1 (fr)
AT (1) ATE205031T1 (fr)
AU (1) AU6447798A (fr)
CA (1) CA2254960C (fr)
DE (1) DE69801477T2 (fr)
WO (1) WO1998039866A1 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0871303A3 (fr) * 1997-04-08 1999-10-27 Victor Demjanenko Procédé pour la détermination de l'atténuation d'un signal modulé par impulsions codées (MIC) sur un canal numérique
WO2000007353A1 (fr) * 1998-07-28 2000-02-10 Conexant Systems, Inc. Procede et dispositif de detection et de determination des caracteristiques d'un canal numerique dans un systeme de communication de donnees
EP1001579A1 (fr) * 1998-11-10 2000-05-17 Siemens Aktiengesellschaft Procédé et dispositif pour déterminer les propriétés d'un canal de transmission
US6332009B2 (en) 1997-09-03 2001-12-18 Conexant Systems, Inc. Method and apparatus for generating a line impairment learning signal for a data communication system

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GB1417627A (en) * 1972-10-24 1975-12-10 Hasler Ag Testing digital-to-analogue and analogue-to-digital convertors in a pcm endstation
US4161627A (en) * 1976-12-30 1979-07-17 Wandel & Goltermann Method of and system for generating digital test signals
US4730302A (en) * 1985-10-17 1988-03-08 Siemens Aktiengesellschaft Monitoring means for digital signal multiplex equipment
US5398234A (en) * 1992-10-21 1995-03-14 Digital Equipment Corporation DS-0 loop-back detection on a DS-1 line
DE4343982C1 (de) * 1993-12-22 1995-08-17 Siemens Ag Anschlußleitungsnetz

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GB1417627A (en) * 1972-10-24 1975-12-10 Hasler Ag Testing digital-to-analogue and analogue-to-digital convertors in a pcm endstation
US4161627A (en) * 1976-12-30 1979-07-17 Wandel & Goltermann Method of and system for generating digital test signals
US4730302A (en) * 1985-10-17 1988-03-08 Siemens Aktiengesellschaft Monitoring means for digital signal multiplex equipment
US5398234A (en) * 1992-10-21 1995-03-14 Digital Equipment Corporation DS-0 loop-back detection on a DS-1 line
DE4343982C1 (de) * 1993-12-22 1995-08-17 Siemens Ag Anschlußleitungsnetz

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Title
INGLE J F: "HOW TO DETECT FRAME SLIPS IN VOICEBAND PCM CHANNELS", DATA COMMUNICATIONS, vol. 17, no. 11, October 1988 (1988-10-01), NEW YORK, US, pages 205/206, 209/210, 217/218, 221/222, XP000032541 *

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0871303A3 (fr) * 1997-04-08 1999-10-27 Victor Demjanenko Procédé pour la détermination de l'atténuation d'un signal modulé par impulsions codées (MIC) sur un canal numérique
US6332009B2 (en) 1997-09-03 2001-12-18 Conexant Systems, Inc. Method and apparatus for generating a line impairment learning signal for a data communication system
US6504886B1 (en) 1997-09-03 2003-01-07 Conexant Systems Inc. Communication of an impairment learning sequence according to an impairment learning sequence descriptor
WO2000007353A1 (fr) * 1998-07-28 2000-02-10 Conexant Systems, Inc. Procede et dispositif de detection et de determination des caracteristiques d'un canal numerique dans un systeme de communication de donnees
US6574280B1 (en) 1998-07-28 2003-06-03 Conexant Systems, Inc. Method and apparatus for detecting and determining characteristics of a digital channel in a data communication system
EP1001579A1 (fr) * 1998-11-10 2000-05-17 Siemens Aktiengesellschaft Procédé et dispositif pour déterminer les propriétés d'un canal de transmission
WO2000030310A3 (fr) * 1998-11-10 2000-08-31 Infineon Technologies Ag Procede et appareil de determination des proprietes d'une voie d'emission de signaux
US7010000B1 (en) 1998-11-10 2006-03-07 Infineon Technologies Ag Method and apparatus of determining properties of a signal transmission channel

Also Published As

Publication number Publication date
CA2254960A1 (fr) 1998-09-11
EP0916202A1 (fr) 1999-05-19
EP0916202B1 (fr) 2001-08-29
AU6447798A (en) 1998-09-22
DE69801477T2 (de) 2002-05-08
DE69801477D1 (de) 2001-10-04
CA2254960C (fr) 2003-01-07
ATE205031T1 (de) 2001-09-15

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